1. Field of the Invention
The present invention relates to a control apparatus for a hybrid vehicle which is mounted in a hybrid vehicle propulsion driven by jointly using an internal-combustion engine and a motor, and wherein the driving force from at least one of the internal-combustion engine and the motor is transmitted to the driving wheels.
2. Description of Related Art
Conventionally, for example, in a hybrid vehicle which comprises an internal-combustion engine and a motor as a power source and wherein the driving force from at least one of the internal-combustion engine and the motor is transmitted to the driving wheels for propulsion, a control apparatus for a hybrid vehicle has been well known which calculates the throttle opening for minimizing the fuel consumption of the internal-combustion engine with respect to the rotating speed of the input shaft of the transmission, and based on this throttle opening and the accelerator operation amount of a driver, allocates the torque required by the power plant (that is, the internal-combustion engine and the motor), to the engine torque required by the internal-combustion engine and to the motor torque required by the motor (for example, refer to Japanese Patent Application Unexamined Publication No. Hei 9-163509.
Incidentally, in a control apparatus for a hybrid vehicle according to an example of the above conventional technique, there is concern that for example, if the timing to start the fuel supply to the internal-combustion engine after completion of a predetermined warming-up operation is set to a predetermined timing according to the engine speed and the engine water temperature (temperature of the cooling water of the internal-combustion engine) regardless of the starting state of the internal-combustion engine, for example normal start of the internal-combustion engine, or restart of the internal-combustion engine where fuel supply is restarted from a temporary fuel supply canceling state, the fuel consumption efficiency may be deteriorated.
For example, in a hybrid vehicle comprising a torque converter equipped with a lock-up clutch wherein the output from one of the internal-combustion engine and the motor is transferred to the transmission through this torque converter, if the setting is such that the fuel supply is started after a predetermined time according to the engine water temperature, has passed from the point in time when it is determined that the engine speed of the internal-combustion engine driven by the motor is greater than a predetermined speed, there may be a problem in that for example, in an operating state where the vehicle is repeatedly made to start and stop frequently, for example such as in a traffic jam, then even in the case where creep travel (travel by means of a creep force) by the driving force of the motor is desired, the internal-combustion engine is restarted with excessive frequency.